It was only a matter of time. Jon Huntsman, the former Utah governor and Obama administration official, has probably known for a long while that he would not be the Republican presidential nominee, at least not this year. It was only 10 days ago when Huntsman said he looks forward to the re-emergence of “a sane Republican Party based on real ideas.”

As a rule, candidates who believe their own party isn’t sane don’t win.

And sure enough, Huntsman, with no prospects of success, no fundraising, and a fleeing staff, has decided to call it a day.

Jon M. Huntsman Jr. will announce Monday that he is ending his bid for the Republican presidential nomination and endorsing Mitt Romney, narrowing the field and erasing a challenge to Mr. Romney from the moderate wing of his party.

Mr. Huntsman, who had hoped to use the South Carolina primary this week to revive his flagging candidacy, informed his advisers on Sunday that he was bowing to political reality and would back Mr. Romney, whom he accused a week ago of putting party ahead of country.

The timing of Huntsman’s departure is a little odd. There’s a debate tonight, which he’d already agreed to participate in, and over the weekend, Huntsman picked up the endorsement of South Carolina’s largest and most influential newspaper.

But the reality of the situation apparently wouldn’t budge. Huntsman put all of his eggs in one basket — betting everything on a strong showing in New Hampshire last week — and failed. There was simply no point in delaying the inevitable any further.